Hey man, Alright, Bandtest.dll is important ! Try and reinstall renegade, Right click it's desktop shortcut and hit properties, Here's a screenshot of what to do next.

Put in the option "Run in Windows XP Service Pack 2 Mode" And then hit apply or okay, After that start up renegade and make sure it downloads the patch! If it can't download the patch, Manually download it from: ftp://ftp.westwood.com/pub/renegade/updates

After the patch has been Installed, Install RenGuard then let it download CorePatch 2 and it's new version!